S2000 Under The Hood S2000 Technical and Mechanical discussions.

Knocking sound at idle (vid)

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Old Mar 26, 2011 | 01:17 AM
  #1  
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Default Knocking sound at idle (vid)

Hi Everyone

I've only had this car for a few weeks and it has starting making the following noise, I posted this up on the UK forum but nobody seems to know what could cause it.

If I start the car from stone cold the engine will be more or less silent, then after 5 - 10min or so of running this noise will start.

http://www.youtube.com/watch?v=-8ROc3y_MUs

If I kill the engine when hot, leave it for 10 and restart it will be silent for about 30 seconds before it starts again making me think it is oil\oil pressure related. I am curently running 5 = 40w full synth.

http://www.youtube.com/watch?v=BLz6hsCfgts

The noise seems to vanish if I rev the engine to anything above idle - say 1200 rpm.

So far I have tried:
  • Sandblasting the TCT
  • Valve clearances
  • Removed the serpentine belt
Nothing helped.

Anyone have any ideas? Could it be a bearing or something *gulp*?

The car seems to run just fine on the road.
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Old Mar 26, 2011 | 02:12 AM
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Originally Posted by Mintyhit
Hi Everyone

I've only had this car for a few weeks and it has starting making the following noise, I posted this up on the UK forum but nobody seems to know what could cause it.

If I start the car from stone cold the engine will be more or less silent, then after 5 - 10min or so of running this noise will start.

http://www.youtube.com/watch?v=-8ROc3y_MUs

If I kill the engine when hot, leave it for 10 and restart it will be silent for about 30 seconds before it starts again making me think it is oil\oil pressure related. I am curently running 5 = 40w full synth.

http://www.youtube.com/watch?v=BLz6hsCfgts

The noise seems to vanish if I rev the engine to anything above idle - say 1200 rpm.

So far I have tried:
  • Sandblasting the TCT
  • Valve clearances
  • Removed the serpentine belt
Nothing helped.

Anyone have any ideas? Could it be a bearing or something *gulp*?

The car seems to run just fine on the road.
Mine has made that noise for the past year (although not as loud as yours appears but i'd imagine thats tjust the recording) despite me trying everything you did yourself. I was terrrified that i had a scored cylinder or broken piston bearings but it never got worse despite some serious abuse and hard driving!!!

Ive resigned myself to it just being the sound of the engine.

One more thing-try take for a drive and rev out to 9k a few times, when i pull over after that it seems quieter!!! Maybe just splashing a bit of oil where it's needed
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Old Mar 26, 2011 | 03:39 AM
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what the f@#k happened to your valve cover?
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Old Mar 26, 2011 | 04:10 AM
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Edwardmcardle: Perhaps mine is a bit louder than yours as I honesty couldn't live with this sound - not much street cred in pulling up in a car that sounds like a single cylinder pizza delivery scooter. :-(

JoeBalls: British weather happend - refurbishing the cover is on my to-do list but not a priority at the mo.
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Old Mar 26, 2011 | 08:23 AM
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you sure you got your valve adjustments right? didn't get my specs right on my valve adjustment and a somewhat similar noise
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Old Mar 26, 2011 | 09:23 AM
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Sounds like tct, noticed when u gave it alittle throttle that the noise went away and came back when you stopped.. If it were a rod or piston the noise would get louder

Also whats up with all those stains on the left side of the head below the valve cover next to the vtec cyl
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Old Mar 26, 2011 | 09:33 AM
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Originally Posted by cyrusakakumar
you sure you got your valve adjustments right? didn't get my specs right on my valve adjustment and a somewhat similar noise
I did wonder so I went out again today and spent another 3 hours painstakingly doing them all again. Twice in a weekend... my back is killing me!

So i'm setting the Exhaust to 0.010 and the inlet at 0.008 on a cold engine as per the specs - I've done clearances before a few time, 95% sure I am doing it right thought I wouldn't discount my own incompetence as a possibility.

Here is how it sounds now... pretty much the same. :-(

http://www.youtube.com/watch?v=I0xVLEJ7m-o

The noise really does not sound like it is coming from the head.
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Old Mar 26, 2011 | 07:47 PM
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Ive only seen youtube videos but is it possibly rod knock due to scored rod/main bearings??
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Old Mar 27, 2011 | 03:29 AM
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+1 doesnt sound like valves nor tct. Sounds like a rod knock to me. Do you have any CEL??? If i were you i would take an OBD scanner and check for any fault codes. Maybe the person who sold the car to you took the CEL bulb out therefore the light never turning on. Anyhow, just get a code scan to be safe> Not to burst your bubble, seems like you might need a rebuild but thats just imho
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Old Mar 27, 2011 | 04:19 AM
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No Cel light on, the light does work - I unplugged a sensor to check.

I am starting to think it is the rod bearings as well - crazy how this has happened only three weeks into ownership. I'm positive it didnt sound like this when I bought it so it must have happens in the last week. I've been driving it hard but not 'track day' hard... I must just be unlucky.

Oh well... So, I am assuming I can do the rod bearings with the engine still in situ by pulling the sump and oil pump. I might try this first if so... I've rebuilt engines before but has always been a long hard expensive job and I'd really like to avoid taking the head off if I can.

Any last ideas about this noise before I can the plunge and get her up on stands?

Cheers
James
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